A possible, but speculative, origin is crustal uplift caused by a plume-like convection cell in a fluid mantle underlying a thin crust.
22.
This has enabled scientists to identify convection cells and other large-scale features such as the large low-shear-velocity provinces near the core mantle boundary.
23.
That leaves the possibility of forming a convection cell, which I guess is plausible since the lightning does dump heat into the air.
24.
:: : The driving force is convection cells, where the core of the Earth cools itself by causing the mantle to " boil ".
25.
:: : : : Due to volcanism, heavier elements are routinely spewed out onto the surface as a result of convection cells within the mantle.
26.
The presence of alteration in all of the extrusive levels but the very highest imply a succession of numerous hydrothermal convection cells active during eruption.
27.
Granules on the photosphere of the Sun are the visible tops of convection cells in the photosphere, caused by convection of plasma in the photosphere.
28.
In the field of fluid dynamics, a "'convection cell "'is the phenomenon that occurs when density differences exist within a body of liquid or gas.
29.
Once conduction is established, the microscopic random movement " spontaneously " becomes ordered on a macroscopic level, forming Benard convection cells, with a characteristic correlation length.
30.
Lately, the convection theory has been much debated as modern techniques based on 3D seismic tomography still fail to recognize these predicted large scale convection cells.
